The present invention relates generally to a method and an apparatus for characterizing the barrier properties of members of combinatorial libraries. More specifically, the present invention relates to a method and an apparatus for performing real-time measurements of the permeability of water vapor into an array of coating materials and coatings, the method and the apparatus utilizing an array of acoustic wave devices.
In the combinatorial discovery of coating materials, such as barrier coating materials, the rapid characterization of the barrier properties of the coating materials and the evaluation of the moisture permeability of the coating materials are of primary importance. The transport of vapors, such as analyte vapors and water vapor, in and through the coatings is typically measured by exposing one side of a given coating to an analyte vapor while nitrogen gas sweeps the other side of the coating and any analyte vapor present in the atmosphere to a detector. The detector measures the rate at which the analyte vapor permeates the coating. Another method measures the amount of an out-gassed vapor present when a coating is deposited onto a non-permeable substrate and exposed to a vapor of interest. These methods, although marginally effective, require the utilization of large areas of coating in order to obtain a measurable signal, provide low measurement sensitivity, and make it difficult to simultaneously characterize the barrier properties of a plurality of coatings, especially to moisture.
Thus, what is needed is a method and an associated apparatus that require the utilization of only small areas of coating in order to obtain a measurable signal, provide relatively high measurement sensitivity, and make it possible to simultaneously characterize the barrier properties of a plurality of coatings, especially to moisture.
The present invention provides a method and an associated apparatus for the real-time characterization of the barrier properties of an array of coatings, the method and the apparatus utilizing an array of acoustic wave devices.
In one embodiment of the present invention, a method for characterizing the barrier properties of an array of coatings includes providing a plurality of acoustic wave devices, wherein each of the plurality of acoustic wave devices comprises at least one surface, and providing a plurality of coating materials suitable for forming a plurality of coatings on the at least one surface of each of the plurality of acoustic wave devices. The method also includes coating each of the plurality of acoustic wave devices with at least one of the plurality of coating materials to form a plurality of coated acoustic wave devices and measuring a predetermined output parameter of each of the plurality of coated acoustic wave devices. The method further includes exposing the plurality of coated acoustic wave devices to an analyte vapor of a predetermined concentration, measuring the predetermined output parameter of each of the plurality of coated acoustic wave devices, and correlating a change in the predetermined output parameter of each of the plurality of coated acoustic wave devices to a barrier property of interest or the moisture permeability of each of the plurality of coatings.
In another embodiment of the present invention, an apparatus for characterizing the barrier properties of an array of coatings includes a plurality of acoustic wave devices, wherein each of the plurality of acoustic wave devices comprises at least one surface, and wherein the plurality of acoustic wave devices are arranged in an array. The apparatus also includes a plurality of coating materials suitable for forming a plurality of coatings on the at least one surface of each of the plurality of acoustic wave devices. The apparatus further includes means for coating each of the plurality of acoustic wave devices with at least one of the plurality of coating materials to form a plurality of coated acoustic wave devices and an array of coatings, and a means for measuring a predetermined output parameter of each of the plurality of coated acoustic wave devices. The apparatus further includes means for exposing the plurality of coated acoustic wave devices to an analyte vapor of a predetermined concentration and a correlation factor operable for correlating a change in the predetermined output parameter of each of the plurality of coated acoustic wave devices to a barrier property of interest or moisture permeability of each of the plurality of coatings of the array of coatings.